Remove "compiled closures" ("cclos") in favor of a simpler mechanism.

Remove "compiled closures" ("cclos") in favor of a simpler mechanism.

The idea is to introduce `gsubrs' whose arity is encoded in their type
(more precisely in the sizeof (void *) - 8 MSBs).  This removes the
indirection introduced by cclos and simplifies the code.

* libguile/__scm.h (CCLO): Remove.

* libguile/debug.c (scm_procedure_source, scm_procedure_environment):
  Remove references to `scm_tc7_cclo'.

* libguile/eval.c (scm_trampoline_0, scm_trampoline_1,
  scm_trampoline_2): Replace `scm_tc7_cclo' with `scm_tc7_gsubr'.

* libguile/eval.i.c (CEVAL): Likewise.  No longer make PROC the first
  argument.  Directly invoke `scm_gsubr_apply ()' instead of jump to the
  `evap(N+1)' label or call to `SCM_APPLY ()'.

* libguile/evalext.c (scm_self_evaluating_p): Remove reference to
  `scm_tc7_cclo'.

* libguile/gc-card.c (scm_i_sweep_card, scm_i_tag_name): Likewise.

* libguile/gc-mark.c (scm_gc_mark_dependencies): Likewise.

* libguile/goops.c (scm_class_of): Likewise.

* libguile/print.c (iprin1): Likewise.

* libguile/gsubr.c (create_gsubr): Use `unsigned int's for REQ, OPT and
  RST.  Use `scm_tc7_gsubr' instead of `scm_makcclo ()' in the default
  case.
  (scm_gsubr_apply): Remove calls to `SCM_GSUBR_PROC ()'.
  (scm_f_gsubr_apply): Remove.

* libguile/gsubr.h (SCM_GSUBR_TYPE): New definition.
  (SCM_GSUBR_MAX): Changed to 33.
  (SCM_SET_GSUBR_TYPE, SCM_GSUBR_PROC, SCM_SET_GSUBR_PROC,
  scm_f_gsubr_apply): Remove.

* libguile/procprop.c (scm_i_procedure_arity): Remove reference to
  `scm_tc7_cclo'; add proper handling of `scm_tc7_gsubr'.

* libguile/procs.c (scm_makcclo, scm_make_cclo): Remove.
  (scm_procedure_p): Remove reference to `scm_tc7_cclo'.
  (scm_thunk_p): Likewise, plus add proper `scm_tc7_gsubr' handling.

* libguile/procs.h (SCM_CCLO_LENGTH, SCM_MAKE_CCLO_TAG,
  SCM_SET_CCLO_LENGTH, SCM_CCLO_BASE, SCM_SET_CCLO_BASE, SCM_CCLO_REF,
  SCM_CCLO_SET, SCM_CCLO_SUBR, SCM_SET_CCLO_SUBR, scm_makcclo,
  scm_make_cclo): Remove.

* libguile/stacks.c (read_frames): Remove reference to `scm_f_gsubr_apply'.

* libguile/tags.h (scm_tc7_cclo): Remove.
  (scm_tc7_gsubr): New.
  (scm_tcs_subrs): Add `scm_tc7_gsubr'.